CN213276262U - Image forming apparatus with a toner supply device - Google Patents

Abstract

The utility model provides an image forming device. The image forming apparatus of an embodiment includes a support shaft, a coupling member, and a detachable member. The support shaft extends in a first direction. The support shaft has a protrusion. The protrusion protrudes in a second direction orthogonal to the first direction. The connecting member is made of an elastic material. The connecting member holds the protrusion. The connecting member is connected to the support shaft in a manner surrounding an outer periphery of the support shaft. The attachment and detachment member is detachably connected to the support shaft via a connection member. Through the utility model discloses, can load and unload image forming device's separation roller easily.

Description

Image forming apparatus with a toner supply device

Technical Field

Embodiments of the present invention relate to an image forming apparatus.

Background

As a paper feed separation mechanism in an image forming apparatus, a rotational separation method is known. In the rotational separation method, a separation roller having a torque limiter is pressed against a paper feed roller. The friction coefficient of the separation roller and the paper feed roller with respect to the sheet is larger than the friction coefficient between the sheets.

When a sheet is not nipped or one sheet is nipped between the separation roller and the paper feed roller, the rotational driving force received by the separation roller via the paper feed roller or the sheet exceeds the set torque of the torque limiter. As a result, the separation roller rotates along with the sheet feeding roller and rotates in the opposite direction to the sheet feeding roller. Thus, when one sheet is nipped, the sheet is fed.

On the other hand, when two sheets enter between the separation roller and the paper feed roller, a slip occurs between the two sheets, and the separation roller stops. Thus, double feeding of the lower sheet is prevented.

The separation roller is supported swingably about a swing fulcrum provided downstream in the sheet conveying direction, and is biased toward the sheet feed roller by a spring or the like.

When the friction coefficient of the surface of the separation roller varies due to abrasion or the like, the separation performance deteriorates. Therefore, the separation roller, which is worn more, needs to be replaced.

For example, the separation roller is held by a holder having a joint detachably connected to a swing fulcrum shaft provided in the paper feeding portion. As the joint, a C-shaped joint is generally used. The C-shaped joint is swingably fitted to an outer peripheral surface of the swing support shaft.

For example, the joint is detachable from the swing support shaft by forming the C-shaped joint with an elastically deformable material and making the opening in the radial direction slightly smaller than the outer diameter of the swing support shaft. In this case, the opening of the joint is attached to and detached from the pivot shaft by advancing and retreating. When the joint is attached and detached, a certain amount of force is required because the joint needs to be elastically deformed.

SUMMERY OF THE UTILITY MODEL

The utility model provides an image forming device capable of easily loading and unloading separation roller.

An image forming apparatus according to an embodiment includes: a support shaft that extends in a first direction and has a protrusion that protrudes in a second direction orthogonal to the first direction; a connecting member made of an elastic material, the connecting member sandwiching a protrusion and being connected to the support shaft in a manner surrounding an outer periphery of the support shaft; and a mounting and dismounting member detachably connected to the support shaft via the connecting member.

Through the utility model discloses, can load and unload image forming device's separation roller easily.

Drawings

FIG. 1 is a schematic sectional view showing an example of the overall configuration of an image forming apparatus according to an embodiment;

FIG. 2 is a perspective view showing an example of a cassette type sheet feeding section (sheet feeding section) in the image forming apparatus according to the embodiment;

FIG. 3 is a perspective view showing an example of a column of a cassette paper feed section in the image forming apparatus according to the embodiment;

FIG. 4 is a perspective view schematically showing an example of a detachable member housing portion and a pressing mechanism provided in a cassette paper feeding portion of an image forming apparatus according to an embodiment;

FIG. 5 is a perspective view schematically showing an example of a removable member housing portion provided in the cassette paper feed portion of the image forming apparatus according to the embodiment;

FIG. 6 is a schematic cross-sectional view taken along line A-A of FIG. 2;

FIG. 7 is a perspective view schematically showing an example of a member for attaching and detaching a cassette paper feed unit in the image forming apparatus according to the embodiment;

FIG. 8 is a schematic view of view B (side view) of FIG. 7;

FIG. 9 is a schematic sectional view showing a positional relationship between a connection member and a support shaft of a cassette paper feeding section of an image forming apparatus according to an embodiment;

FIG. 10 is a schematic perspective view showing an example of a manual paper feed unit (paper feed unit) in the image forming apparatus according to the embodiment;

FIG. 11 is a schematic perspective view showing a main part of a manual paper feed unit in the image forming apparatus according to the embodiment;

FIG. 12 is a schematic perspective view of a manual paper feed unit in the image forming apparatus according to the embodiment;

FIG. 13 is a perspective view showing a state in which a manual paper feed section is partially cut away in the image forming apparatus according to the embodiment;

FIG. 14A is a schematic sectional view showing an example of a member for attaching and detaching a manual paper feed unit in the image forming apparatus according to the embodiment;

FIG. 14B is a schematic sectional view showing an example of a member for attaching and detaching the manual paper feeding section in the image forming apparatus according to the embodiment;

fig. 15 is a schematic sectional view illustrating a detaching operation of a connection member at a cassette paper feed portion in an image forming apparatus according to an embodiment, fig. 15(a) is a schematic sectional view in which an replacer rotates a separation roller unit about each support shaft clockwise in the drawing to an upper swing limit, and fig. 15(b) is a schematic sectional view in which the replacer further rotates a holder clockwise in the drawing;

fig. 16 is a perspective view schematically illustrating a detaching operation of a connection member in a manual paper feed portion in the image forming apparatus according to the embodiment;

fig. 17 is a perspective view schematically illustrating a detaching operation of the connection member in the manual paper feeding unit in the image forming apparatus according to the embodiment.

Detailed Description

The image forming apparatus of an embodiment includes a support shaft, a coupling member, and a detachable member. The support shaft extends in a first direction. The support shaft has a protrusion. The protrusion protrudes in a second direction orthogonal to the first direction. The connecting member is made of an elastic material. The connecting member holds the protrusion. The connecting member is connected to the support shaft in a manner surrounding an outer periphery of the support shaft. The attachment and detachment member is detachably connected to the support shaft via a connection member.

(embodiment mode)

Hereinafter, an image forming apparatus according to an embodiment will be described with reference to the drawings.

Fig. 1 is a schematic cross-sectional view showing an example of the overall configuration of an image forming apparatus according to an embodiment. In the following drawings, the same or corresponding structures are denoted by the same reference numerals unless otherwise specified.

As shown in fig. 1, the image forming apparatus 100 of the present embodiment includes a control panel 1, a scanner section 2, a printer section 3, a sheet feeding section 4, a conveying section 5, a manual paper feeding unit 10, and a main body control section 6.

Hereinafter, when referring to the relative position in the image forming apparatus 100, the X1 direction, the X2 direction, the Y1 direction, the Y2 direction, the Z1 direction, and the Z2 direction shown in the drawing may be used. The X1 direction is a direction from left to right when standing on the front side (front side of the paper surface in fig. 1) of the image forming apparatus 100. The X2 direction is opposite to the X1 direction. The Y1 direction is a direction from the back to the front of the image forming apparatus 100. The Y2 direction is opposite to the Y1 direction. The Z1 direction is the vertically upward direction. The Z2 direction is a vertically downward direction. The direction of the X1(Y1, Z1) and the X2(Y2, Z2) is not limited to the X (Y, Z) direction, and may be simply referred to as the X (Y, Z) direction. In addition, the Y direction (including the Y1 direction and the Y2 direction) is referred to as a first direction, the X direction (including the X1 direction and the X2 direction) is referred to as a second direction, and the first direction is orthogonal to the second direction.

Hereinafter, a plane having a normal in the X direction is referred to as a YZ plane, a plane having a normal in the Y direction is referred to as a ZX plane, and a plane having a normal in the Z direction is referred to as an XY plane. The ZX plane is parallel to a conveying direction of a sheet S described later in the image forming apparatus 100. The XY plane is a horizontal plane.

The control panel 1 operates the image forming apparatus 100 by a user performing an operation.

The scanner unit 2 reads image information of a copy target as the brightness and darkness of light. The scanner section 2 outputs the read image information to the printer section 3.

The printer section 3 forms an image on the sheet S based on image information from the scanner section 2 or the outside.

The printer section 3 forms an output image (toner image) using a developer containing toner. The printer section 3 transfers the toner image onto the surface of the sheet S. The printer section 3 applies heat and pressure to the toner image on the surface of the sheet S to fix the toner image on the sheet S.

The sheet supply section 4 supplies the sheets S to the printer section 3 one by one in accordance with the timing at which the printer section 3 forms the toner image.

The sheet feeding unit 4 includes sheet feeding cassettes 20A, 20B, and 20C and a plurality of cassette sheet feeding units 21 (sheet feeding units).

The paper feed cassettes 20A, 20B, and 20C store sheets S of various sizes.

The cassette paper feeding portions 21 are provided above the ends of the paper feeding cassettes 20A, 20B, and 20C in the X1 direction, respectively. Each cassette paper feed section 21 has a pickup roller 22B, and a paper feed roller 22A and a separation roller 43 for separating and feeding sheets S.

Each pickup roller 22B conveys a sheet S necessary for forming an image from the paper feed cassettes 20A, 20B, and 20C to a nip portion between the paper feed roller 22A and the separation roller 43.

Each paper feed roller 22A conveys the sheet S conveyed to the nip portion to the conveying portion 5.

When conveying the two sheets S to the nip, each separation roller 43 separates one sheet S from the two sheets S by a rotational separation method. Therefore, the separation roller 43 is rotatably supported so as to be capable of pressing the paper feed roller 22A, and is biased toward the paper feed roller 22A with a substantially constant force by a spring described later. The separation roller 43 is configured such that the separation roller 43 does not rotate in the direction opposite to the paper feed roller 22A due to the inter-sheet friction force generated between the paper feed roller 22A and the separation roller 43 and the sheet S. Further, the separation roller 43 is configured such that a frictional force generated between the separation roller 43 and the sheet S in contact with the separation roller 43 is larger than an inter-sheet frictional force.

As a result, when the two sheets S are conveyed between the paper feed roller 22A and the separation roller 43 by the pickup roller 22B, the one sheet S in contact with the paper feed roller 22A slides against the sheet S on the lower layer side, and is conveyed by the conveying force of the paper feed roller 22A. During this time, the sheet S on the lower layer side stops together with the separation roller 43. Therefore, even if two sheets S are conveyed between the paper feed roller 22A and the separation roller 43, only one sheet S that is in contact with the paper feed roller 22A is separated.

After the overall configuration of image forming apparatus 100 is described, the detailed configuration of cassette paper feed unit 21 will be described.

The conveying unit 5 includes a conveying roller 23 and a registration roller 24. The conveying section 5 conveys the sheet S supplied from the sheet supply section 4 to the registration rollers 24.

The registration rollers 24 convey the sheet S in accordance with the timing at which the printer section 3 transfers the toner image onto the sheet S.

The conveying roller 23 brings the leading end of the sheet S in the conveying direction into contact with the nip portion N of the registration roller 24. The conveying rollers 23 align the position of the tip of the sheet S in the conveying direction by bending the sheet S.

The registration rollers 24 align the tip of the sheet S fed out from the conveying rollers 23 at the nip portion N. The registration rollers 24 convey the sheet S to a transfer unit 28 described later.

The conveying unit 5 has conveying paths 30A, 30B, 30C, and 30D. After another configuration of the printer section 3 is described, the conveying paths 30A, 30B, 30C, and 30D will be described.

The printer section 3 includes image forming sections 25Y, 25M, 25C, and 25K, an exposure section 26, an intermediate transfer belt 27, a transfer section 28, a fixing device 29, and a transfer belt cleaning unit 35.

The image forming portions 25Y, 25M, 25C, and 25K are arranged in this order along the X1 direction.

Each of the image forming portions 25Y, 25M, 25C, 25K forms a toner image to be transferred onto the sheet S on the intermediate transfer belt 27.

The image forming portions 25Y, 25M, 25C, and 25K each have a photosensitive drum 7. The image forming portions 25Y, 25M, 25C, and 25K form a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image, respectively, on the photosensitive drum 7.

A charger, a developing unit 8, a primary transfer roller, a cleaning unit, and a static eliminator are disposed around each photosensitive drum 7. The primary transfer roller faces the photosensitive drum 7. The intermediate transfer belt 27 is sandwiched between the primary transfer roller and the photosensitive drum 7. The exposure section 26 is disposed below the charger and the developing unit 8.

The toner cartridges 33Y, 33M, 33C, and 33K are disposed above the image forming units 25Y, 25M, 25C, and 25K. The toner cartridges 33Y, 33M, 33C, and 33K store yellow, magenta, cyan, and black toners, respectively.

The toners in the toner cartridges 33Y, 33M, 33C, and 33K are supplied to the image forming units 25Y, 25M, 25C, and 25K through toner supply pipes (not shown).

The exposure unit 26 irradiates the surface of each charged photosensitive drum 7 with laser light. Light emission control is performed on the laser light based on image information. The exposure section 26 may also adopt a structure that emits LED light instead of laser light. In the example shown in fig. 1, the exposure section 26 is disposed below the image forming sections 25Y, 25M, 25C, and 25K.

Image information corresponding to yellow, magenta, cyan, and black is supplied to the exposure portion 26.

The exposure portion 26 forms an electrostatic latent image on the surface of each photosensitive drum 7 based on image information.

The intermediate transfer belt 27 is an endless belt. The intermediate transfer belt 27 is tensioned by a plurality of rollers that abut against the inner circumferential surface. The intermediate transfer belt 27 is stretched flat. The inner peripheral surface of the intermediate transfer belt 27 abuts against the backup roller 28a at the farthest position in the X1 direction in the bridging direction. The inner peripheral surface of the intermediate transfer belt 27 abuts against the transfer belt roller 32 at the farthest position in the X2 direction in the span direction.

The backup roller 28a forms a part of the transfer section 28 described later. The support roller 28a guides the intermediate transfer belt 27 to the secondary transfer position.

The transfer belt roller 32 guides the intermediate transfer belt 27 to a cleaning position.

On the illustrated lower surface side of the intermediate transfer belt 27, the image forming portions 25Y, 25M, 25C, and 25K other than the primary transfer rollers are arranged in this order in the X1 direction. The image forming portions 25Y, 25M, 25C, and 25K are disposed at intervals in a region between the transfer belt roller 32 and the backup roller 28 a.

When the toner image reaches the primary transfer position, a transfer bias is applied to each of the primary transfer rollers of the image forming portions 25Y, 25M, 25C, and 25K. Each primary transfer roller transfers (primary transfer) the toner image on the surface of each photosensitive drum 7 onto the intermediate transfer belt 27.

In the intermediate transfer belt 27, a transfer section 28 is disposed at a position adjacent to the image forming section 25K.

The transfer section 28 includes a support roller 28a and a secondary transfer roller 28b (roller). The secondary transfer roller 28b and the support roller 28a sandwich the intermediate transfer belt 27. The position where the secondary transfer roller 28b and the intermediate transfer belt 27 abut against each other is a secondary transfer position.

The transfer section 28 transfers the charged toner image on the intermediate transfer belt 27 onto the surface of the sheet S at the secondary transfer position. The transfer section 28 applies a transfer bias to the secondary transfer position. The transfer section 28 transfers the toner image on the intermediate transfer belt 27 to the sheet S by a transfer bias.

The fixing device 29 applies heat and pressure to the sheet S. The fixing device 29 fixes the toner image transferred onto the sheet S by the heat and pressure. The fixing unit 29 is disposed above the transfer unit 28.

The transfer belt cleaning unit 35 faces the transfer belt roller 32. The transfer belt cleaning unit 35 sandwiches the intermediate transfer belt 27. The transfer belt cleaning unit 35 scrapes off the toner on the surface of the intermediate transfer belt 27.

Conveyance paths 30A, 30B for conveying the sheet S from below to above are formed in this order between the registration roller 24 and the transfer portion 28 and between the transfer portion 28 and the fixing device 29, respectively.

A conveyance path 30C for discharging the sheet S in the X2 direction is formed above the fixing device 29. A discharge tray 9 on which the sheet S discharged from the conveyance path 30C is placed is provided below the exit of the conveyance path 30C in the X2 direction.

Above the fixing device 29, a conveying direction switching unit 31 for switching the conveying direction of the sheet S is provided.

A conveying path 30D for conveying the sheet S from the conveying direction switching portion 31 to the registration rollers 24 is formed inside the printer portion 3 on the X1 direction side of the conveying paths 30A and 30B. The conveyance path 30D is used, for example, to reverse the sheet S having an image formed on the surface thereof and supply it to the registration rollers 24 when double-sided printing is performed.

Each of the conveying paths 30A, 30B, 30C, and 30D includes a conveying guide portion facing each other and sandwiching the sheet S, and a conveying roller provided as necessary.

The manual paper feed unit 10 feeds a sheet P on which an image is to be formed to the printer section 3.

The manual paper feed unit 10 includes a manual paper feed tray 10a and a manual paper feed unit 11 (paper feed unit).

The manual paper feed tray 10a is rotatable about a rotation axis extending in the Y direction. When the manual feed tray 10a is used, the manual feed tray 10a rotates clockwise as shown by a solid line to be opened. Sheets P of various sizes can be placed on the opened manual feed tray 10 a.

When the manual paper feed tray 10a is not used, the manual paper feed tray 10a is rotated counterclockwise in the drawing as shown by the two-dot chain line, and is accommodated in the side portion of the printer section 3 in the X1 direction.

The manual paper feed unit 11 separates and feeds the sheet P placed on the manual paper feed tray 10a, and conveys the sheet P toward the registration rollers 24. The above-described rotary separation method is used for the separation of the sheets P in the manual paper feed unit 11, as in the cassette paper feed unit 21.

The manual paper feed unit 11 includes a manual paper feed roller unit 12 and a separation roller 43. The manual feed roller unit 12 has a pickup roller 12B and a feed roller 12A.

The pickup roller 12B and the feed roller 12A have the same structure as the pickup roller 22B and the feed roller 22A except for feeding the sheet P.

The separation roller 43 in the manual paper feed portion 11 has the same structure as the separation roller 43 in the cassette paper feed portion 21, except that it abuts against the paper feed roller 12A.

After the overall configuration of image forming apparatus 100 is described, the detailed configuration of manual paper feed unit 11 will be described.

The main body control section 6 controls each apparatus part of the image forming apparatus 100.

Next, the detailed configuration of the cassette paper feed unit 21 will be described.

Fig. 2 is a perspective view schematically showing an example of a cassette paper feed section (feeding section) in the image forming apparatus according to the embodiment. Fig. 3 is a perspective view schematically showing an example of a column of the cassette paper feed section in the image forming apparatus according to the embodiment.

As shown in fig. 2, the cassette paper feed section 21 further includes an upper cover 21a and a support column 21 b.

The cassette paper feed unit 21 is fixed to a printer main body (not shown) between a front plate and a rear plate (not shown) of the printer unit 3.

The upper cover 21a is a plate-like member long in the Y direction. The upper cover 21a is longer than the conveyance width of the sheet S (not shown). The upper cover 21a is disposed so as to cover the paper feed roller 22A and the pickup roller 22B from above.

The paper feed roller 22A is fixed to the tip of the drive shaft 22A extending in the Y direction in the Y1 direction below the center portion of the upper cover 21a in the longitudinal direction. The drive shaft 22A receives a driving force from a drive motor (not shown) in the printer main body portion to rotate the paper feed roller 22A.

The pickup roller 22B is provided so as to be swingable about the rotation center of the feed roller 22A. The pickup roller 22B is connected to the sheet feed roller 22A via a transmission mechanism. The pickup roller 22B rotates in the same direction as the feed roller 22A in conjunction with the rotation of the feed roller 22A.

The stay 21b has the same length as the upper cover 21 a. The support column 21b is fixed to the upper cover 21a below the end of the upper cover 21a in the X1 direction.

As shown in fig. 3, a separation roller unit housing portion 21A is formed at the longitudinal center portion of the stay 21 b. The separation roller unit housing portion 21A houses the separation roller unit 40 (detachable member) including the separation roller 43 in a detachable manner.

The detailed structure of the separation roller unit housing portion 21A will be described with reference to fig. 4 to 6.

Fig. 4 is a schematic perspective view showing an example of the attachable/detachable member housing portion and the pressing mechanism provided in the cassette paper feeding portion of the image forming apparatus according to the embodiment. Fig. 5 is a schematic perspective view showing an example of a removable member accommodating portion provided in the cassette paper feeding portion of the image forming apparatus according to the embodiment. Fig. 6 is a schematic sectional view taken along line a-a in fig. 2.

As shown in fig. 4 and 5, the separation roller unit housing portion 21A (detachable member housing portion) is a recess portion facing the bottom surface portion 21e of the pillar 21b when viewed in the direction Z2.

The separation roller unit housing portion 21A is formed by being surrounded by the first wall 21fF (see fig. 5), the second wall 21fB (see fig. 4), and the third wall 21 h.

The separation roller unit housing portion 21A is opened in the Z1 direction and the X2 direction.

First wall 21fF and second wall 21fB are flat plate portions parallel to the ZX plane. The first wall body 21fF and the second wall body 21fB have the same outer shape as each other when viewed in the Y direction. The first wall 21fF and the second wall 21fB face each other in the Y direction. First wall 21fF is disposed on the Y1 direction side of separation roller unit housing section 21A. Second wall 21fB is disposed on the Y2 direction side of separation roller unit accommodating portion 21A.

The third wall 21h is a flat plate portion parallel to the YZ plane. The third wall 21h is disposed so as to be sandwiched between the first wall 21fF and each end of the second wall 21fB on the X1 direction side.

Both ends of the third wall 21h in the Y direction may be joined to the first wall 21fF and the second wall 21fB, respectively. However, in the example shown in fig. 4 and 5, both ends of the third wall 21h in the Y direction are separated from the first wall 21fF and the second wall 21 fB.

As shown in fig. 5, a first support shaft 21dF (support shaft) is provided at a portion of the first wall 21fF near the third wall 21 h. The first support shaft 21dF extends from the Y2-directional surface of the first wall body 21fF toward the Y2 direction (first direction), i.e., the first support shaft 21dF is provided upright on the first wall body 21 fF. The distal end portion of the first support shaft 21dF in the extending direction is connected to the third wall 21h via the first support portion 21g extending toward the third wall 21h in the X1 direction.

The first protrusion 21cF (protrusion) protrudes in the X1 direction (second direction) on the surface on the X1 direction side of the first support shaft 21 dF. The first protrusion 21cF extends to penetrate the gap between the first wall 21fF and the third wall 21 h. The first protrusion 21cF connects the first wall 21fF and the third wall 21h to each other. In addition, the first protrusion 21cF connects the first support shaft 21dF with at least one of the first wall 21fF and the third wall 21 h.

As shown in cross-section in fig. 6, the first support shaft 21dF is a cylinder with a diameter d 1. The first protrusion 21cF is a flat plate parallel to the XY plane, and has a thickness t1 when viewed in the Y direction. However, t1 is less than d 1. The outer peripheral surface s of the first support shaft 21dF excluding the first protrusions 21cF is a cylindrical surface forming the surface of a cylinder having a diameter d 1.

The shape of the first protrusion 21cF is not particularly limited as long as t1 < d1 is satisfied and the first protrusion 21cF is not damaged by an external force acting on the first protrusion 21cF by a mounting and demounting operation described later.

As shown in fig. 4, a second support shaft 21dB (support shaft) is provided at a portion of the second wall body 21fB near the third wall body 21 h. The second support shaft 21dB extends from the surface of the second wall body 21fB in the Y1 direction toward the Y1 direction (first direction), and the second support shaft 21dB is provided upright on the second wall body 21 fB. The distal end portion in the extending direction of the second support shaft 21dB is connected to the third wall body 21h via a second support portion 21gB extending toward the third wall body 21h in the X1 direction.

The second protrusion 21cB (protrusion) protrudes in the X1 direction (second direction) on the surface of the second support shaft 21dB on the X1 direction side. The second protrusion 21cB extends to penetrate the gap between the second wall 21fB and the third wall 21 h. The second protrusion 21cB connects the second wall 21fB and the third wall 21h to each other. In addition, the second protrusion 21cB connects the second support shaft 21dB with at least one of the second wall 21fB and the third wall 21 h.

The second support shaft 21dB, the second protrusion 21cB, and the second support portion 21gB have a shape that is plane-symmetrical with the support shaft 21dF, the first protrusion 21cF, and the first support portion 21g with respect to a plane that is parallel to the ZX plane and bisects the distance between the first wall body 21fF and the second wall body 21 fB.

Therefore, the second support shaft 21dB and the first support shaft 21dF are spaced apart from each other in the length direction and are coaxially arranged. Although the cross section is not particularly shown, the diameter of the second support shaft 21dB is d1 as with the first support shaft 21dF, and the thickness of the second protrusion 21cB is t1 as with the first protrusion 21 cF.

Hereinafter, the first support shaft 21dF and the second support shaft 21dB may be simply referred to as support shafts 21d, and the first projection 21cF and the second projection 21cB may be simply referred to as projections 21 c.

As shown in fig. 4, inclined surfaces 21i are formed on both sides of the separation roller unit housing portion 21A in the Y direction above the support post 21 b. Each inclined surface 21i is a plane extending in an inclined direction inclined toward the Z1 direction as advancing in the X1 direction.

Each inclined surface 21i is provided with a conveyance guide 21j for guiding conveyance of the sheet S (not shown) from below.

Such a support column 21b may be formed by resin molding.

A pressure lever 51 and a coil spring 50 (spring) are disposed on a bottom surface portion 21e of the support 21 b.

The pressure lever 51 includes a pressure arm 51a, a rotation shaft 51b, and a locking portion 51 c.

The pressing arm 51a applies a force in the X2 direction to the separation roller unit 40 described later.

The rotation shaft 51b supports the pressure arm 51a so that the pressure arm 51a can swing along the bottom surface 21 e. When the bottom surface portion 21e is provided with a hole portion, the rotation shaft portion 51b may be constituted by a shaft portion that is rotatably fitted in the hole portion. When the bottom surface portion 21e is provided with a shaft-like projection, the rotation shaft portion 51b may be constituted by a hole portion that is rotatably fitted in the shaft-like projection.

The locking portion 51c locks a coil spring 50 described later. For example, the locking portion 51c may be formed of a protrusion protruding from the vicinity of the rotation shaft portion 51b in the X1 direction.

The coil spring 50 is constituted by an extension coil spring. Hooks 50a, 50b are formed at both end portions of the coil spring 50.

The hook 50a is locked to a tensioner 52, and the tensioner 52 is fixed to the end of the support column 21b in the Y1 direction so as to be movable in the Y direction.

The hook 50b is locked to a locking portion 51c of the pressure lever 51.

The tensioner 52 is fixed to the stay 21b at a position where the coil spring 50 extends longer than the natural length. Therefore, when viewed in the direction Z2, the moment of force generated by the elastic restoring force of the coil spring 50 acts on the pressure lever 51 clockwise about the rotation shaft 51 b.

The biasing force applied to the pressure lever 51 by the coil spring 50 is set in accordance with a pressing force required from the separation roller 43 to be described later to the paper feed roller 22A.

Next, the separation roller unit 40 will be explained.

Fig. 7 is a perspective view schematically showing an example of a member for attaching and detaching the cassette paper feed unit in the image forming apparatus according to the embodiment. Fig. 8 is a schematic diagram of view B (side view) in fig. 7.

As shown in fig. 7, the separation roller unit 40 has a shaft 43a, a separation roller 43, a torque limiter 44, and a holder 41.

The shaft 43a coaxially supports a separation roller 43 and a torque limiter 44, which will be described later, on the center axis O43. The shaft 43a is fixed to a retainer 41 described later at both ends in the axial direction.

The separation roller 43 has a substantially cylindrical shape, and has an outer diameter larger than the diameter of the shaft 43 a. An elastic body layer, such as an elastic body capable of generating a necessary frictional force between the sheet S and the paper feed roller 22A, is provided on the outer periphery of the separation roller 43.

The minimum driving torque required for clockwise rotation of the torque limiter 44 as viewed in the Y2 direction is set with respect to the rotational driving of the separation roller 43 about the shaft 43 a. In the example shown in fig. 7, the torque limiter 44 is disposed on the Y2 direction side of the separation roller 43.

The minimum driving torque is smaller than the torque generated by the conveying force from the paper feed roller 22A and larger than the torque generated by the friction between the two sheets S sandwiched between the paper feed roller 22A and the separation roller 43.

The structure of the torque limiter 44 is not particularly limited as long as the minimum driving torque as described above can be set.

The holder 41 has a front side plate 41a, a rear side plate 41B, a cover 41c, a first connecting portion 42F (connecting member, first connecting member), and a second connecting portion 42B (connecting member, second connecting member).

The front side plate 41a is provided on the side of the holder 41 in the Y1 direction. The front plate 41a fixes the end of the shaft 43a in the Y1 direction.

The rear side plate 41b is provided on the side of the holder 41 in the Y2 direction. The rear side plate 41b fixes the end of the shaft 43a in the Y2 direction.

The rear side plate 41b has a shape that is plane-symmetrical with the front side plate 41a with respect to a plane that is parallel to the ZX plane and that bisects the distance between the front side plate 41a and the rear side plate 41 b.

The cover 41c is made of a curved plate covering the lower surface of the holder 41. The cover 41c connects lower end portions of the front side plate 41a and the rear side plate 41b to each other in the Y direction.

As shown in fig. 3, the projection 41A projects at a position corresponding to a longitudinally intermediate portion of the separation roller 43 on the lower side of the cover 41 c.

As shown in fig. 8, the projection 41A includes a protruding piece 41d and a locking projection 41 e.

The protruding piece 41d is a sheet-like body that inclines in the X1 direction as it goes forward in the Z2 direction from the end of the cover 41c in the X2 direction.

The locking projection 41e extends in a plate shape parallel to the ZX plane from the center of the protruding piece 41d in the Y direction toward the X1 direction.

The tip portion 41F of the locking projection 41e in the X1 direction is positioned between the shaft 43a and the first connecting portion 42F in the X direction.

In the attached state of the separation roller unit 40, the tip end portion 41f is provided at a position abutting against the pressure arm 51 a. The tip portion 41f transmits a moment generated by the urging force from the pressing arm 51a to the separation roller unit 40.

As shown in fig. 6, the first connecting portion 42F is provided at one end portion of the holder 41 in the longitudinal direction of the separation roller 43, and the first connecting portion 42F is provided at the end portion of the front side plate 41a on the X1 direction side. The shape of the first connecting portion 42F is not particularly limited as long as it can sandwich the first protrusion 21cF and connect with the first protrusion 21cF of the first support shaft 21dF in a manner of surrounding the outer periphery of the first support shaft 21 dF.

The first connecting portion 42F has a first snap-fit joint (first snap joint) 42a and a second snap-fit joint (second snap joint) 42 b. The first connecting portion 42F is made of an elastic material.

As shown in fig. 8, the shape of the inner peripheral surface of the first snap-fit joint 42a is a circular arc shape along the upper outer peripheral surface of the first support shaft 21dF when viewed in the Y2 direction.

Similarly, the inner peripheral surface of the second snap-fit joint 42b is shaped like a circular arc along the lower outer peripheral surface of the first support shaft 21 dF. Thereby, the first snap-fit joint 42a and the second snap-fit joint 42b are respectively located on opposite sides (both sides in the radial direction) of the first support shaft 21 dF.

Therefore, the first connecting portion 42F protrudes in a C-shape in the X1 direction from the end of the front side plate 41 a. The inner peripheral surface of the first connecting portion 42F is a smoothly curved surface that covers the outer peripheral surface s of the first support shaft 21dF over a range of central angles greater than one hundred and eighty degrees. Specifically, the inner peripheral surface 42c of the first connection portion 42F is shaped like an arc centered on the central axis O42 when viewed in the Y2 direction. The radius of the inner peripheral surface 42c is about half the diameter of the first support shaft 21 dF.

An opening 42d (gap) is formed between a circumferential curved distal end surface (distal end portion) 42e of the first snap-fit joint 42a and a circumferential curved distal end surface (distal end portion) 42f of the second snap-fit joint 42 b.

The width of the opening portion 42d is wider than the width (thickness) of the first protrusion 21cF in the circumferential direction when viewed in the Y direction, and is narrower than the outer diameter of the first support shaft 21 dF.

Since the first connecting portion 42F is made of an elastic material, when at least one of the first snap-fit joint 42a and the second snap-fit joint 42b is elastically deformed, the width of the opening portion 42d can be increased. When the width of the opening portion 42d becomes wider than the outer diameter of the first support shaft 21dF, the first connection portion 42F is detachable from the first support shaft 21dF from the side opposite to the first protrusion 21 cF.

Since the outer peripheral surface s of the first support shaft 21dF is a cylindrical surface that can be slidably fitted to the inner peripheral surface 42c, the inner peripheral surface 42c is slidably fitted to the outer peripheral surface s when the first connection portion 42F is attached to the first support shaft 21 dF. At this time, since the inner diameter of the inner peripheral surface 42c is substantially equal (including equal) to the outer diameter of the first support shaft 21dF, the central axis O42 of the first connection portion 42F is substantially coaxial (including coaxial) with the central axis O21d of the first support shaft 21 dF.

The first connection portion 42F attached to the first support shaft 21dF is swingable about the central axis O21d within the range of the difference in dimension in the circumferential direction between the opening portion 42d and the first projection 21 cF.

The shapes of the distal end surfaces 42e and 42F and the opening 42d are not particularly limited as long as a swing range equal to or larger than a swing range (hereinafter referred to as a minimum swing range) necessary for the first connection portion 42F can be obtained.

The minimum swing range of the first connecting portion 42F is a range in which: the separation roller 43 held by the holder 41 can abut against the paper feed roller 22A at a position facing the paper feed roller 22A arranged in the conveyance path of the sheet S including the mounting error and the component error and can nip one sheet S having the maximum thickness of the feedable sheet S between the paper feed roller 22A and the separation roller 43.

However, in view of the ease of attachment and detachment of the separation roller unit 40, the swing range of the first connection portion 42F may be wider than the minimum swing range.

The minimum width of the opening portion 42d when viewed in the Y direction defines a pull-out resistance when the first connecting portion 42F is pulled out from the first support shaft 21 dF. More preferably, the pull-out resistance is as large as possible within a range that does not hinder the attachment and detachment of the separation roller unit 40.

As shown in fig. 9, the minimum width of the opening portion 42d may be w1 as viewed in the Y direction. However, w1 is greater than t1 and less than d 1.

More preferably, the opening portion 42d is shaped such that the distance from the center line C42d of the opening portion 42d gradually increases from the inside to the outside in the radial direction of the first connection portion 42F as viewed in the Y direction, that is, the distance from the center line C42d of the opening portion 42d to the tip end faces 42e and 42F gradually increases from the inside to the outside in the radial direction of the first support shaft 21 dF. For example, the tip end surfaces 42e, 42f may extend in the radial direction with respect to the central axis O42 as viewed in the Y direction.

In the example shown in fig. 9, the tip end surfaces 42e, 42f are respectively half the minimum width w1 from the center line C42d in the vicinity of the radially innermost side and are parallel to and opposed to each other, and are inclined obliquely in the radial direction passing through the center axis O42 in the radially outer side.

The inclination angles of the tip end surfaces 42e, 42f with respect to the center line C42d are acute angles θ, respectively.

In the first connection portion 42F, the distance between the center of the inner peripheral surface 42C and the center of the shaft 43a is L (L is a symbol schematically indicating a numerical value of the distance and is not shown in the drawing), and the center line C42d is provided at a position rotated by an angle Φ in the clockwise direction with respect to a line segment between the center of the connection shaft 43a and the center of the inner peripheral surface 42C. Here, Φ is an acute angle. That is, in a state where the first connecting portion 42F is attached to the first support shaft 21dF, the center line C42d of the opening portion 42d is inclined by Φ in the Z2 direction with respect to a straight line connecting the center axis O21d as the center of the first support shaft 21dF and the center axis O43 as the center of the separation roller 43 as viewed in the Y direction.

Here, the sizes of L and Φ are appropriately set according to the size of the separation roller unit housing portion 21A and the like. For example, L may be a distance slightly longer than the radius of the separation roller 43. For example, Φ may be an angle orthogonal to the facing direction between the paper feed roller 22A and the separation roller 43.

Although the first link portion 42F is described above, the second link portion 42B has a shape that is plane-symmetrical with the first link portion 42F with respect to a plane that is parallel to the ZX plane and that bisects the distance between the front side plate 41a and the rear side plate 41B, and therefore the second link portion 42B is provided at the other end portion of the holder 41 in the longitudinal direction of the separation roller 43. That is, the second connecting portion 42B has first and second snap- fit joints 42a and 42B, which are plane-symmetrical with the first and second snap- fit joints 42a and 42B of the first connecting portion 42F, respectively.

Therefore, detailed description of each part of the second connection portion 42B is omitted.

Hereinafter, the first connection portion 42F and the second connection portion 42B may be simply referred to as a connection portion (connection member) 42.

The holder 41 having such a structure can be formed of, for example, a resin molded product. However, the holder 41 may have a composite structure of a plurality of parts. For example, each of the connecting portions 42 may be a separate member fixed to the front side plate 41a and the rear side plate 41 b.

In the separation roller unit 40, each connecting portion 42 connects each support shaft 21d from the X2 direction side of each support shaft 21d, and the separation roller unit 40 is detachably connected to the support shaft 21d via the connecting portion 42. In such a mounted state, the separation roller unit 40 is swingable about the center axis O21d in the ZX plane, that is, the separation roller unit 40 is connected to be swingable about the support shaft 21 d. As shown in fig. 9, the separation roller 43 can be moved to the positions of the separation rollers 43', 43 ″ indicated by the two-dot chain lines by the oscillation of the separation roller unit 40.

In the attached state, a pressing force f acts on the distal end portion 41f from the pressing arm 51a (not shown) in the X2 direction. Therefore, the separation roller unit 40 receives the moment of the clockwise force centered on the center axis O21d as viewed in the Y2 direction. As a result, in a state where the sheet S (not shown) is not being fed, the separation roller 43 presses the paper feed roller 22A from below, that is, the coil spring 50 urges the tip end portion 41f of the holder 41 via the pressing arm 51a in a direction in which the separation roller 43 presses the paper feed roller 22A. Thereby, a nip is formed between the separation roller 43 and the paper feed roller 22A.

The pressing force of the separation roller 43 against the paper feed roller 22A and the urging force of a coil spring 50 (not shown) corresponding to the pressing force are set in advance so that the width of the nip portion becomes an appropriate value.

Next, the detailed configuration of the manual paper feed unit 11 will be described.

Fig. 10 is a schematic perspective view showing an example of a manual paper feed unit (paper feed unit) in the image forming apparatus according to the embodiment. Fig. 11 is a schematic perspective view showing a main part of a manual paper feed unit in the image forming apparatus according to the embodiment. Fig. 12 is a schematic perspective view of a manual paper feed unit in the image forming apparatus according to the embodiment. Fig. 13 is a schematic perspective view showing a state in which a manual paper feed portion of the image forming apparatus according to the embodiment is partially cut. Fig. 14A and 14B are schematic cross-sectional views showing an example of a member for attaching and detaching the manual paper feed unit in the image forming apparatus according to the embodiment.

Fig. 10 shows a state in which the manual paper feed tray 10a is opened. Guide plates 10b and 10c for guiding both ends of the sheet P (not shown) in the Y direction are provided on the upper surface of the manual feed tray 10 a. The guide plates 10b and 10C can be moved in line symmetry with a conveyance center line C10 that bisects the distance therebetween in the Y direction as a symmetry axis.

The manual paper feed unit 11 is provided near the tip end of the manual paper feed tray 10a in the X2 direction. The pickup roller 12B, the feed roller 12A (not shown), and the separation roller 43 (not shown) of the manual feed portion 11 are positioned on the conveyance center line C10 when viewed in the Z direction.

As shown in fig. 11, in a state where the inner cover 11a and the manual feed roller unit 12 are removed, the separation roller unit 13 (detachable member) including the separation roller 43 is exposed below the opening portion formed at the lower end portion of the side cover 3 a.

The separation roller unit 13 is fixed to a support column 11b disposed inside the printer section 3. The strut 11b is covered with an inner cover 11a disposed below the side cover 3a from the X1 direction. The support column 11b is fixed between a front side plate and a rear side plate of the printer section 3 (not shown).

In the inner cover 11a, a cover 11m is detachably provided below the opening portion so as to cover the X1 direction side of the separation roller unit 13.

As shown in fig. 12, a paper feed guide 11e is formed over the support 11b in the Y direction, and the paper feed guide 11e feeds a sheet P (not shown) to the registration rollers 24 (not shown).

A separation roller unit housing portion 11A (removable member housing portion) is formed at a central portion in the longitudinal direction (Y direction) of the support 11 b. The separation roller unit housing portion 11A houses the separation roller unit 13 in a manner such that the separation roller unit 13 is detachable.

The separation roller unit housing portion 11A is a recess that surrounds the separation roller unit 13 when viewed in the Z2 direction.

The separation roller unit housing portion 11A is formed by being surrounded by the first wall 11fF, the second wall 11fB, the third wall 11h, and the fourth wall 11 i.

The first wall 11fF and the second wall 11fB are flat plate portions parallel to the ZX plane. The first wall body 11fF and the second wall body 11fB have the same outer shape as each other when viewed in the Y direction. The first wall 11fF and the second wall 11fB face each other in the Y direction. The first wall 11fF is disposed on the Y1 direction side of the separation roller unit housing portion 11A. The second wall 11fB is disposed on the Y2 direction side of the separation roller unit housing portion 11A.

As shown in fig. 13 and 14A, the third wall 11h is a flat plate portion inclined in the X2 direction as it advances in the Z1 direction.

As shown in fig. 12, the third wall 11h is disposed so as to be sandwiched between the first wall 11fF and the end portions of the second wall 11fB on the X2 direction side.

Both ends of the third wall 11h in the Y direction are joined to the first wall 11fF and the second wall 11fB, respectively.

In the upper portion of the third wall body 11h, on the side closer to the Y2 direction with respect to the first wall body 11fF, a first shaft supporting plate 11kF made of a flat plate parallel to the ZX plane protrudes in the X1 direction.

In the upper portion of the third wall body 11h, on the side closer to the Y1 direction with respect to the second wall body 11fB, a second shaft supporting plate 11kB made of a flat plate parallel to the ZX plane protrudes in the X1 direction.

The fourth wall 11i is disposed so as to be sandwiched between the first wall 11fF and the end portions of the second wall 11fB on the X1 direction side.

Both ends of the fourth wall 11i in the Y direction are joined to the first wall 11fF and the second wall 11fB, respectively.

An opening 11j that penetrates the fourth wall 11i in the Z direction is formed in an intermediate portion of the fourth wall 11i in the Y direction, the intermediate portion being close to the second wall 11 fB.

In the support 11b, a plate-like portion 11g parallel to the XY plane is provided below the opening 11j (on the Z2 direction side).

As shown in fig. 14A, a first support shaft 11dF (support shaft) and a first protrusion 11cF (protrusion) are provided between the first shaft support plate 11kF and the first wall 11fF (not shown).

The first support shaft 11dF and the first projection 11cF are the same members as the first support shaft 21dF and the first projection 21cF in the cassette type sheet feeding portion 21 except for being provided between the first shaft support plate 11kF and the first wall body 11 fF.

For example, the outer diameter of the first support shaft 11dF is d1, and the thickness of the first protrusion 11cF in the Z direction is t 1.

However, the first support shaft 11dF is disposed on the X1 direction side of the third wall 11 h. The first protrusion 11cF extends in the X2 direction from the side surface on the X2 direction side of the first support shaft 11 dF.

As shown in fig. 14B, a second support shaft 11dB (support shaft) and a second protrusion 11cB (protrusion) are provided between the second shaft support plate 11kB and the second wall body 11fB (not shown).

The second support shaft 11dB and the second protrusion 11cB are the same members as the second support shaft 21dB and the second protrusion 21cB in the cassette type paper feeding section 21, except for being arranged between the second shaft support plate 11kB and the second wall body 11 fB.

The second support shaft 11dB, the second protrusion 11cB, and the second shaft support plate 11kB have a shape that is plane-symmetrical with the first support shaft 11dF, the first protrusion 11cF, and the first shaft support plate 11kF with respect to a plane that is parallel to the ZX plane and bisects the distance between the first wall body 11fF and the second wall body 11 fB.

Therefore, the second support shaft 11dB is disposed coaxially with the first support shaft 11 dF. That is, the respective center axes of the first support shaft 11dF and the second support shaft 11dB are aligned on the center axis O11d extending in the Y direction.

As in the case of the first support shaft 11dF and the first protrusion 11cF, the diameter of the second support shaft 11dB and the thickness of the second protrusion 11cB in the Z direction are d1 and t 1.

Hereinafter, the first support shaft 11dF and the second support shaft 11dB may be simply referred to as support shafts 11d, and the first projection 11cF and the second projection 11cB may be simply referred to as projections 11 c.

As shown in fig. 13, the separation roller unit 13 has a holder 14 instead of the holder 41 of the separation roller unit 40.

Hereinafter, the detailed structure of the separation roller unit 13 will be described centering on the difference from the separation roller unit 40.

The separation roller 43 and the torque limiter 44 in the separation roller unit 13 have the same structure as the separation roller 43 and the torque limiter 44 in the separation roller unit 40, except that they are arranged in order in the Y1 direction.

As shown in fig. 14A and 14B, the holder 14 includes a front plate 14A (see fig. 14A), a rear plate 14B (see fig. 14B), a cover 14c, a first connection portion 15F (connection member, first connection member, see fig. 14A), a second connection portion 15B (connection member, second connection member, see fig. 14B), and a spring locking portion 13e instead of the front plate 41A, the rear plate 41B, the cover 41c, the first connection portion 42F, the second connection portion 42B, and the projection 41A of the holder 41.

Hereinafter, the first connection portion 15F and the second connection portion 15B may be simply referred to as a connection portion (connection member) 15.

The front side plate 14a is provided on the side of the holder 14 in the Y1 direction. The front side plate 14a fixes the end of the shaft 43a in the Y1 direction.

The rear side plate 14b is provided on the side of the holder 14 in the Y2 direction. The rear side plate 14b fixes the end of the shaft 43a in the Y2 direction.

The rear side plate 14b has a shape that is plane-symmetrical with the front side plate 14a with respect to a plane that is parallel to the ZX plane and that bisects the distance between the front side plate 14a and the rear side plate 14 b.

The cover 14c is formed of a curved plate covering the lower surface of the holder 14. The hood 14c connects lower end portions of the front side plate 14a and the rear side plate 14b to each other in the Y direction.

As shown in fig. 14A, the first connecting portion 15F is provided at the end portion on the X2 direction side of the front side plate 14A. Like the first connection portion 42F, the first connection portion 15F has a first snap-fit joint 42a and a second snap-fit joint 42 b. However, the opening portions 42d of the first snap-fit joint 42a and the second snap-fit joint 42b in the first connecting portion 15F face the X2 direction.

As shown in fig. 14B, the second connecting portion 15B is provided at the end portion on the X2 direction side of the rear side plate 14B. Like the second connection portion 42B, the second connection portion 15B has a first snap-fit joint 42a and a second snap-fit joint 42B. However, the opening portions 42d of the first snap-fit joint 42a and the second snap-fit joint 42B in the second connecting portion 15B face the X2 direction.

The first connection portion 15F and the second connection portion 15B are made of an elastic material.

The spring locking portion 13e includes a plate-like portion that locks, from above, an upper end of a coil spring 53 (spring) locked to an upper surface of the plate-like portion 11 g. The spring retaining portion 13e is connected to an end of the hood 14c in the X1 direction.

As shown in fig. 13, the spring retaining portion 13e is provided at a position corresponding to an intermediate portion in the longitudinal direction of the separation roller 43 in the Y direction. However, in fig. 13, the coil spring 53 is not shown (the same as in fig. 12).

When the separation roller unit 13 is attached to the manual paper feeding unit 11, the coil spring 53 biases the spring locking portion 13e in the Z1 direction. As the coil spring 53, a compression coil spring is used. The natural length of the coil spring 53 is larger than the distance from the lower surface of the spring retaining portion 13e to the surface of the plate-like portion 11g when the separation roller 43 and the paper feed roller 12A abut against each other.

The biasing force of the coil spring 53 generated when the coil spring 53 is attached between the plate-like portion 11g and the spring locking portion 13e is set in advance so that the width of the nip portion between the separation roller 43 and the paper feed roller 12A becomes an appropriate value.

The retainer 14 having such a structure may be formed of a resin molded product as in the retainer 41, or may be formed by combining a plurality of members.

The separation roller unit 13 is mounted in the same manner as the separation roller unit 40 except that each connecting portion 15 is connected to each support shaft 11d from the X1 direction side of each support shaft 11d and is biased toward the paper feed roller 12A by the coil spring 53. At the time of mounting, the separation roller unit 13 can swing in the ZX plane centering on the center axis O11 d.

Next, the operation of the image forming apparatus 100 will be described centering on the attaching and detaching operation of the separation roller units 40 and 13.

First, an image forming operation of the image forming apparatus 100 will be briefly described.

In the image forming apparatus 100 shown in fig. 1, image formation is started by an operation of the control panel 1 or an external signal. The image information is acquired by the scanner section 2 reading a copy target and is sent to the printer section 3, or is acquired from the outside and is sent to the printer section 3. The printer section 3 feeds the sheet S in the sheet feeding section 4 or the sheet P in the manual paper feeding unit 10 to the registration rollers 24 based on an operation of the control panel 1 or an external signal and on a control signal generated by the main body control section 6. Hereinafter, a case of supplying the sheet S will be described as an example.

When an operation input for image formation is performed from the control panel 1, the main body control portion 6 controls to start paper feeding from the sheet feeding portion 4 and perform image formation.

The image forming units 25Y, 25M, 25C, 25K form electrostatic latent images on the respective photosensitive drums 7 based on image information corresponding to each color. Each electrostatic latent image is developed by the developer 8. Thereby, a toner image corresponding to the electrostatic latent image is formed on the surface of each photosensitive drum 7.

Each toner image is primarily transferred onto the intermediate transfer belt 27 by each transfer roller. The toner images are sequentially overlapped without causing color deviation with the movement of the intermediate transfer belt 27, and are conveyed to the transfer portion 28.

The sheet S is supplied from the registration rollers 24 to the transfer section 28. The toner image that has reached the transfer portion 28 is secondarily transferred onto the sheet S. The secondary-transferred toner image is fixed on the sheet S by the fixing device 29. Thereby, an image is formed on the sheet S.

When such image formation is repeatedly performed, each separation roller 43 is worn by friction or the like at the time of the separation operation. When the abrasion of each separation roller 43 exceeds the allowable limit, the separation performance deteriorates. Therefore, each separation roller 43 is replaced as necessary.

In the present embodiment, the separation roller 43 of the cassette paper feed portion 21 is replaced for each separation roller unit 40, and the separation roller 43 of the manual paper feed portion 11 is replaced for each separation roller unit 13.

First, a method of replacing the separation roller unit 40 will be described.

Fig. 15 is a schematic sectional view for explaining the operation of detaching the connection member in the cassette paper feed portion in the image forming apparatus according to the embodiment.

The replacer first detaches the paper feed roller 22A so that the separation roller unit 40 can rotate upward.

Thereafter, as shown in fig. 15(a), the exchanger rotates the separation roller unit 40 about each support shaft 21d clockwise in the drawing to the upper swing limit. At this time, the replacer holds a part of the holder 41, for example, to rotate the separation roller unit 40. For example, the replacer may move the protrusion 41A with a finger to rotate the separation roller unit 40.

Although the Y1-direction end of the separation roller unit 40 is shown in fig. 15, exactly the same operation is performed at the Y2-direction end of the separation roller unit 40.

When the separation roller unit 40 rotates to the swing limit of the upper side, the tip end surface 42e of the first snap-fit joint 42a abuts against the upper surface of the projection 21 c.

In this state, since each of the connection portions 42 is not elastically deformed, the width of the opening portion 42d is maintained at w 1.

Thereafter, as shown in fig. 15(b), the replacer rotates the holder 41 further clockwise in the drawing. At this time, the replacer does not need to pull out the holder 41 in the X2 direction.

When such a rotational force is applied, the first snap-fit joint 42a is elastically deformed, so that the width of the opening portion 42d is expanded to w2 which is wider than w 1.

The tip end portion of the second snap-fit joint 42b slides along the lower surface of the support shaft 21 d. This further expands the width of the opening 42 d.

At this time, since the replacer applies a force to the holder 41 apart from the connecting portion 42, for example, like the projection 41A, the holder 41 forms a lever having a contact portion between the tip end surface 42e and the projection 21c as a fulcrum and a contact portion between the tip end portion of the second snap-fit joint 42b and the support shaft 21d as an action point. Therefore, the replacer can open the opening portion 42d with a light force corresponding to the lever ratio at the portion of the holder 41 to be gripped.

For example, in the case of mounting the separation roller unit 40 on a strut in the related art in which the protrusion 21c is not provided on each support shaft 21d in fig. 15, since no lever is formed regardless of which portion of the holder 41 of the separation roller unit 40 is gripped, it is necessary to apply a force equal to or more than pull-out resistance to elastically deform the connection portion 42 and pull it out from the support shaft 21 d.

According to the detachment method of the present embodiment, the burden on the replacer can be reduced as compared with such a detachment method in the related art.

Further, according to the detachment method in the related art, since the separation roller unit 40 is accelerated in the pull-out direction by the pulling force when the connection portion 42 is pulled out from the support shaft 21d, there is a possibility that the hand of the replacer placed in the pull-out direction hits against the components inside the apparatus.

On the other hand, according to the detaching method of the present embodiment, since the separation roller unit 40 moves in the rotational direction when the second snap-fit joint 42b is disengaged from the support shaft 21d, even if momentum is imparted, it is possible to avoid the hand of the replacement person from hitting other parts inside the apparatus.

Further, in the disassembling method in the prior art, a replacer tends to grasp the surface of the separation roller so as to apply force at the time of loading and unloading. In this case, there is a possibility that the surface of the installed separation roller is damaged.

On the other hand, it is also known that a thin portion smaller than the width of the opening of the joint is formed in the pivot shaft, and the joint is attached to and detached from the pivot shaft through the thin portion. In this case, since the area of the cylindrical outer peripheral surface of the rotation support shaft is reduced, there is a possibility that stable swing performance is impaired, for example, the swing center becomes easy to shift.

Further, the strength of the rotation fulcrum is reduced by the thin portion. Since the separation roller in operation is constantly subjected to an external force from the paper feed roller or the sheet, the rotation support shaft may be easily damaged. There is also a possibility that the rotation fulcrum may be easily damaged when an unexpected external force is applied during the replacement work.

According to the detachment method of the present embodiment, such problems in the related art can be suppressed.

When the width w2 of the opening portion 42d reaches d1, each connecting portion 42 moves in the rotational direction and is separated from each support shaft 21 d. Thereby, the separation roller unit 40 is detached.

In the above description, in order to make the operation easier to understand, the operation of rotating the holder 41 is divided into a first operation of bringing the distal end surface 42e into contact with the projection 21c and a second operation of further rotating the holder 41 to elastically deform the connecting portion 42. However, the first action and the second action may not be performed separately. The changer may continuously perform the first action to the second action.

As described above, the separation roller unit 40 of the present embodiment can be easily detached by the replacer even in the printer section 3. However, the separation roller unit 40 may be removed from the cassette paper feeding portion 21 outside the printer portion 3 as described above after the cassette paper feeding portion 21 is removed from the printer portion 3.

Although not particularly illustrated, in the case of installing the separation roller unit 40, the above-described actions may be reversely performed. In this case, since the holder 41 functions as a lever, the mounting can be performed with a lower load than when the detachment method in the related art is performed in the reverse order.

However, the replacer can install the separation roller unit 40 by performing the disassembling method in the related art in the reverse order. In this case, since a force acts on the holder 41 in the press-in direction, the mounting can be easily performed even under the same load as compared with the pull-out. Further, since the position of the separation roller unit 40 is fixed when the mounting is completed, there is little possibility that the hand of the replacer hits other parts inside the apparatus.

Next, a method of replacing the separation roller unit 13 will be described with reference to fig. 11, 16, and 17.

Fig. 16 and 17 are schematic perspective views for explaining the operation of detaching the connection member in the manual paper feeding section in the image forming apparatus according to the embodiment.

The separation roller unit 13 can be detached from the manual paper feeding unit 11, similarly to the separation roller unit 40. However, the detaching direction differs depending on the arrangement of the separation roller unit 13 in the manual paper feeding unit 11.

The exchanger first removes the manual paper feed tray 10a, the manual paper feed roller unit 12, and the cover 11m (see fig. 11).

Thereafter, as shown in fig. 16, the replacer rotates the separation roller unit 13 upward by holding the spring locking portion 13 e. Thereby, the same first action and second action as described above are performed. As a result, as shown in fig. 17, the separation roller unit 13 is detached from the manual paper feeding unit 11.

In fig. 16 and 17, for the sake of simplicity, the components such as the side cover 3a and the inner cover 11a are not shown. The above replacement operation can be performed without detaching the manual paper feed unit 11 from the printer unit 3.

In fig. 16 and 17, the coil spring 53 is not shown. The coil spring 53 may be detachable together with the separation roller unit 13, or may be separated from the spring retaining portion 13e and left in the manual sheet feeding portion 11.

Since the separation roller unit 13 and the manual paper feed unit 11 are connected to the support shaft 11d by the connecting portion 15 similar to the connecting portion 42 and the support shaft 21d, the same action is exerted during the attaching and detaching operation as in the separation roller unit 40.

In the separation roller units 13, 40, a straight line connecting the center axis O42 and the center axis O43 is inclined at an angle Φ in the Z2 direction with respect to the center lines C11d, C42d of the protrusions 11C, 21C.

In the case of the manual paper feed unit 11, the upper portion is opened in a wide range, and therefore, the manual paper feed unit 11 can be easily replaced without being removed.

In the manual paper feeding unit 11, since the separation roller unit housing portion 11A has the fourth wall 11i, the holder 14 cannot move in the X1 direction. Therefore, the disassembling method in the related art or the mounting method in the reverse order thereof cannot be performed.

As shown in fig. 14A, particularly in the case of the separation roller unit 13, the spring retaining portion 13e is arranged in the X1 direction with respect to the protrusion 41A in the separation roller unit 40. Therefore, since the replacer grips the spring locking portion 13e, the turning radius of the acting point is larger than that in the case of gripping the protrusion 41A in the separation roller unit 40. Therefore, the lever ratio becomes large. The replacer can detach the separation roller unit 13 more easily than the separation roller unit 40.

As described above, according to the image forming apparatus 100 of the present embodiment, the separation roller 43 can be easily attached and detached.

Further, the projections 21c project from the support shafts 21d and connect the third wall 21h and the first wall 21fF and the third wall 21h and the second wall 21fB, respectively. Therefore, the protrusions 21c and the support shafts 21d are reinforced by the first wall 21fF, the second wall 21fB, and the third wall 21 h. Therefore, even if the thickness of the projection 21c and the outer diameter of the support shaft 21d are small, they are less likely to be damaged by external force during attachment and detachment.

The same applies to the protrusions 11c and the support shafts 11d in the separation roller unit 13.

Therefore, when the support posts 21b, 11b are formed by resin molding, the protrusions 21c, 11c and the support shafts 21d, 11d may also be formed by resin molding.

According to at least one embodiment described above, an image forming apparatus in which the separation roller can be easily attached and detached can be provided.

A modification of the above embodiment will be described below.

In the description of the embodiment, the manual paper feed unit 11 and the cassette paper feed unit 21 are both of the rotation separation type. However, a rotary separation system may be used for at least one of the manual paper feed unit 11 and the cassette paper feed unit 21.

When a separation method other than the rotational separation method is used for one paper feed unit, for example, an angular claw method, a separation pad method, a separation roller method, or the like can be used.

In the description of the embodiment, the attachment/detachment member is biased by the tension coil spring or the compression coil spring. However, the loading and unloading member may be urged by a spring other than a coil spring.

In the description of the embodiment, the retainer of the separation roller is biased by the spring. However, the retainer may not be urged by a spring. For example, when the holder may be made of an elastically deformable material and the elastic deformation of the connection member is suppressed to such an extent as not to disengage the connection member from the support shaft, the separation roller may be urged toward the sheet feeding roller using an elastic restoring force generated by the elastic deformation of the holder itself, instead of the spring.

In the description of the embodiment, the detachable member is biased by the spring. However, when the attachment/detachment member only needs to be detachably attached to any portion of the image forming apparatus, the attachment/detachment member may not be urged by a spring.

In the description of the embodiment, the support shaft, the coupling member, and the attachment/detachment member are provided in the paper feeding unit having the paper feeding roller and the separation roller. However, the support shaft, the connecting member, and the attachment/detachment member may be provided in a portion other than the paper feed portion in the image forming apparatus. In this case, the loading and unloading member may not have any roller including the separation roller, but may include a roller other than the separation roller.

In the case where the roller is not included, the attaching and detaching member may not have a roller housing portion for housing the roller.

In the description of the embodiments, it is described that the connection member has the first snap-fit joint and the second snap-fit joint, and the connection member is C-shaped when viewed in the first direction. However, the outer peripheral surfaces of the first snap-fit joint and the second snap-fit joint may not be circular arc-shaped as long as the inner peripheral surfaces thereof are circular arc-shaped as viewed in the first direction.

Further, the first snap-fit joint and the second snap-fit joint are not particularly limited as long as they can be elastically deformed when the attachment and detachment member is detached and can be coaxially connected with the central axis of the support shaft when the attachment and detachment member is attached. For example, since surface contact with the support shaft is possible, it is more preferable that the inner peripheral surfaces of the first snap fit joint and the second snap fit joint are circular arc-shaped when viewed in the first direction.

However, the inner peripheral surfaces of the first snap-fit joint and the second snap-fit joint may be formed of a flat surface or a curved surface capable of making line contact in the circumferential direction or the axial direction of the support shaft.

In the description of the embodiment, it is described that tip end portions of the first snap-fit joint and the second snap-fit joint in the connection member face each other in the circumferential direction. However, the first snap-fit joint and the second snap-fit joint may be arranged at different positions in the axial direction of the support shaft.

In the description of the embodiment, the connection part is constituted by the first connection part and the second connection part, and accordingly, the support shaft has the first support shaft and the second support shaft, and the protrusion has the first protrusion and the second protrusion. However, the number of each of the connecting member, the support shaft, and the protrusion is not limited to two, as long as there is at least one each. For example, the number of each of the coupling member, the support shaft, and the projection may be one or three or more, respectively.

For example, with respect to the plurality of connection members, at least one of one support shaft and a protrusion may be used.

While several embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various manners, and various omissions, substitutions, combinations, and changes can be made without departing from the gist of the present invention. These embodiments and modifications are included in the scope and gist of the present invention, and are included in the present invention and the equivalent scope thereof described in the claims.

Claims (10)

1. An image forming apparatus is characterized by comprising:

a support shaft that extends in a first direction and has a protrusion that protrudes in a second direction orthogonal to the first direction;

a connecting member made of an elastic material, the connecting member sandwiching a protrusion and being connected to the support shaft in a manner surrounding an outer periphery of the support shaft; and

a loading and unloading member detachably connected to the support shaft via the connection member.

2. The image forming apparatus according to claim 1,

the coupling member includes first and second snap joints respectively located on opposite sides of the support shaft,

tip end portions of the first snap joint and the second snap joint form a gap that is wider than a width of the protrusion in a circumferential direction of the support shaft and narrower than an outer diameter of the support shaft as viewed in the first direction,

the attachment/detachment member is connected to the support shaft so as to be pivotable about the support shaft.

3. The image forming apparatus according to claim 2,

the inner circumferential surfaces of the first engaging joint and the second engaging joint are formed in an arc shape when viewed in the first direction.

4. The image forming apparatus according to claim 3,

the outer peripheral surface of the support shaft excluding the protrusions is formed of a cylindrical surface that can be slidably fitted to the inner peripheral surfaces.

5. The image forming apparatus according to claim 2,

the distance from the center line of the gap to each of the tip portions gradually increases from the inside to the outside in the radial direction of the support shaft as viewed in the first direction.

6. The image forming apparatus according to claim 2, further comprising:

a manual paper feeding unit having a manual paper feeding tray on which a sheet is placed, and a paper feeding roller and a separation roller which separate and feed the sheet,

the support shaft, the coupling member, and the attachment and detachment member are provided in the manual paper feed unit,

the attachment/detachment member further includes a holder that holds the separation roller at a position facing the paper feed roller arranged in the sheet conveyance path.

7. The image forming apparatus according to claim 2, further comprising:

a paper feeding part having a paper feeding roller and a separation roller for separating and feeding sheets,

the support shaft, the coupling member, and the attachment/detachment member are provided in the sheet feeding portion,

the attachment/detachment member further includes a holder that holds the separation roller at a position facing the paper feed roller arranged in the sheet conveyance path.

8. The image forming apparatus according to claim 7,

the connecting member has a first connecting member and a second connecting member provided at both end portions of the holder in a longitudinal direction of the separating roller,

the support shaft has a first support shaft and a second support shaft that are disposed apart from each other in the longitudinal direction and are coaxial,

the protrusions are provided on the first support shaft and the second support shaft, respectively.

9. The image forming apparatus according to claim 7,

the sheet feeding section is further provided with a spring that urges the holder,

the spring biases the holder in a direction in which the separation roller presses the paper feed roller.

10. The image forming apparatus according to claim 8,

the paper feeding section further includes a column provided with a loading and unloading member accommodating section for accommodating the loading and unloading member,

the removable member housing section includes: a first wall body on which the first support shaft is erected, a second wall body on which the second support shaft is erected, and a third wall body arranged between the first wall body and the second wall body,

a first protrusion connects the first support shaft with at least one of the first wall and the third wall,

a second protrusion connects the second support shaft with at least one of the second wall body and the third wall body.

Images